Contacts- have they done more harm than good?

[Lynn White]

Hi Rosemary... no probs with your typing.. all understood!

Most of what you say is referring to RGP sclerals which is hardly the lens of choice for the usual mildly myopic High Street patient. What you may not appreciate is that around 20 years + ago, speciality contact lens fitting was "taken back" into the hospital system. When I first qualified, I could fit a "hospital" type patient in normal practice and use the HES hospital form to claim back my expenses after the patient had paid the hospital rate. From around 20 years + ago onwards, the patient had to be referred to a hospital clinic to be fitted - as it is now.

This has meant that during this last 20 years, not many optoms in the High Street have had ready access to the more complex contact lens fittings and since the onslaught of supermarket supply of disposables, many practices are now abandoning even disposable fittings. This is a crisis that the optometric professional bodies are addressing right now. Many multiple practices do not "allow" RGP fittings of any type, let alone KC fittings. They will often refer "difficult" patients on to a central practice many miles away to a specialist fitter.

Its not that some fitters "do not remember" how to fit speciality lenses - rather that the market has changed and as optometry is now dominated by multiples who are driven by turnover, practitioners are "not allowed" to fit these lenses. I recently worked as a locum for a well known respected multiple and saw a KC patient. I knew exactly what I wanted to fit this patient but the "purchasing" side of the business did not deal with those kind of lenses and so I was simply told I could not fit this patient. End of.

And no, I am not talking "hard lens" fittings, I am talking about RGP lenses. Most optoms converted to RGP material as soon as it was available. The issues I am talking about relate to the rigidity of the material, not its oxygen permeability. (For those not up to speed on materials, RGPs are rigid lenses that transmit oxygen whereas PMMA rigid lenses transmit zero oxygen!)

Overall, Rosemary, you are talking from personal experience of scleral lenses. I am talking from a research point of view of RGP corneal lenses. The two types are completely different in the way they interact on the cornea. Scleral lenses do not rest on the cornea or flex in the same kind of way as RGP corneal lenses. An RGP corneal lens interacts with the cornea in ways a scleral lens does not.

Much of the work done on this subject is by Professor Charles McMonnies in Australia - here is the link to his paper

http://journals.lww.com/claojournal/Abstract/2006/01000/Biomechanically_Coupled_Curvature_Transfer_in.12.aspx

Corneal RGP lenses only flatten the cornea if they are fitted flat. Steep fitted lenses "suck" the cornea into the steep shape. Scleral lenses are designed differently - they "vault" the cornea.

Lynn

[Fordy]

Thanks for all your replies,certainly food for thought there. However my concerns about the lenses are still there and would like to ask Lynn if all these factors also apply to the hybrid type lenses that I am now wearing ,as I have stated in the past that this seems to be the last option as they will not use the new generation of soft lenses, much to my frustration.
Thanks

Fordy

[GarethB]

Fordy

There have been a few cases now where people have gone the soft rout privatly and then turned up at their next hospital appointment wearing them, thus demonstarting that soft lenses work for them. The hospitals have then agreed to continue the care of these poeple and to provide new lenses if they are needed.

As far as the concerns you have about hybrid lenses, I would think Lynns comments still apply as you can still have flat fitting lenses on the RGP part and even steep fitting. I always throught the soft edge was to aid lens stability and also to help with comfort for example if there were no soft skirt the edge of the lens would be rubbing on the eye lid or something.

[rosemary johnson]

Seventh time lucky (i rhink it's got to).... - I hope!
Lynn: been aware for ages it depended where you lived whether lens fitted a) in High St or b) by hospital CL dept.
Hadn't realised such a time-factor to this geog distribution too.
(Where I come from, only just bringing it back in hospt recently).
SO expertise may still exist but, as in your own case, have its hands tied by bureaucracy.
Or have gone to work in hosp or regional specialist centre miles away?!
Think some confusion later: you said first you weren't talking aout "hard lenses" but RGP in particular; then you say the issues you'd posted about previously were reelated to the rigidity of the material not is gas permeability or otherwise.
>>
That was my point - the phenomena being related to ridgd material, not gas permeability.
SO presumably PMMA (or glass) wold have same effect (or they'd be better, in that respect at least!)
In other words - I think we're in agreement here!
As for sclerals - I'm well aware that the THEORY is they vault over the cornea. As it happens mine don't - I'm one of the (few?) people who break all the rules as that's never worked, and mine are fitted close with big contact zones (in my own eyes, at least, untill it came to the grafted one which vaults. But I can't wear that for other reasons).
Wish you could see them - .

Fordy: sorry, we digress from your question.
It is possible your eye's been "moulded" by the lenses.
However, as in Gareth's case, corenas do "unmould" if the hard lenses are left out.
SO it isn't permanent.
This is a different phenomenon from the changes in structure of the cornea itself coming from the natural advance of KC (which doesn't unmould).
And unfortunately can just go on a spurt at unpredictable times.
Rosemary

[Lynn White]

Well we are almost there Rosemary...

Rigid lenses (and indeed soft) have differing effects depending on their oxygen transmission - PMMA has ZERO transmission which is why they are not really a good idea.

Actually I wouldn't mind seeing your lenses... will Pm you

Lynn

[Andrew MacLean]

Lynn

Do people still use PMMA lenses?

Andrew

[Lynn White]

I still come across people who do which is why I use the present tense. They have the advantage of being a really stable material and hard wearing, so they last years. RGP lenses tend to warp after only a couple of years and are more easily scratched, so it has always been the case that some people really hold onto their PMMAs.

What does surprise me is that some practitioners still fit them. Their rationale is that many people suffer no ill consequences at all from wearing PMMA - but like many things in life - there is no easy way to identify a person who will have problems 15 years down the line.

Lynn

[Steven Williams]

Hi Fordy,

Do contact lenses do more harm than good

I suppose my question is does being fitted with RGP/Hybrid lenses carry a risk of worsening the condition, and if so why was I not warned?

Sorry to hear of your negative experience. You are not alone. You raise three questions.

Its now 26 years ago since my bilateral KC was diagnosed and still I have not found any contact lenses that are comfortable or found a top quality KC specialist who is able to prescribe a contact lens which is confortable, does not aggravate my eyes and allows me to function normally at work. I'm still waiting to discover where in the UK the centres of excellence of treating and caring for KCers are. This forum imo is quiet on the subject and of naming top quality KC healthcare specialists in the UK.

Contact lenses do improve the vision and are certainly better than doing this as KC becomes more advanced. So yes they can do good but there is also a risk that they can do harm.

Most street opticians are not prepared to take the risk of prescribing contact lenses and it is not profitable because of the amount of time which is required.

Your question is a key question imo "does being fitted with RGP/Hybrid lenses carry a risk of worsening the condition" and is one that I first asked the wearing of plastc in my eyes was first raised. I've never received a convincing and confident no it does not yet from anyone.

Every KC case is unique. My take is yes it does increase the risk of exaccerbating the condition and this risk increases as:-

1. the degree of skill and experience of the KC specialist lens optom/fitter decreases
2. the lubrication in the eye decreases. If you suffer from dry eyes as I do this becomes more of a problem.
3. the KC progresses and the cone becomes steeper and more difficult for the optom/fitter.

If you are wearing lenses and getting pain, listen to your body and take them out. You are pressurised to build up wearing time and it becomes an endurance test.

The most confortable lenses and best vision I found were the mini scleral rgp lenses which basically sit on a lubricated well of solution sandwiched between the eye and lens, this removes any friction and abrasion as well as providing a lens.. They are the most expensive lenses.

As I am not able to refer/recommend a top quality KC optom/fitter (they must be out there but I have not yet found one) my advice would be cope as long as you are able to with your glasses and only try contact lenses when your level of vision due to the KC falls below a threshold which does not enable you to carry on (eg. if your corrected vision with glasses falls below the driving test limit, if you need to drive to do your work).

If you have dry eyes try to get that problem sorted before wearing lenses.

Consider KC stabilisation options like CCL before wearing lenses.

Find a top quality KC optom/fitter who consistently gets successful results in fitting KCers.

Should you have been warned about the risks of contact lens wear for Kcers?
If its a professional caring healthcare system without any doubt YES imo.

I hope that you find my comments helpful

Peace, truth & respect

[Lynn White]

Several points to answer here.

First Fordy:

Most of what I said relates to hybrids as well - in fact ANY contact lens of ANY material will impact in some way on an eye that is softer than normal. The trick is working out the degree. Why will they not use soft lenses?

Steven: what you say is interesting. One thing I will say straight away is that in ANY health related area, it is exceedingly difficult for any patient group to highlight the "Top Players" in the field simply because one person's hero is another's worst enemy. There is no practitioner on earth who can please all of the patients all of the time - for the simple reason that life is not that tidy. For KC in particular, one person may rave about a particular lens type whilst another will have had a bad experience with it and recommend another type whole heartedly. Clashes of personality also mean that just because someone gets on famously with one specialist it does not guarantee that another person will also do so.

The basic fact is that we have a subsidised NHS system for KC lenses in the UK which most people decide they want to stick with. In the way of the NHS, this is not as convenient or flexible as a private service - but it IS considerably cheaper. There are private optoms who work exclusively with KC but they are very far and few between simply because most people stay within the NHS - its chicken and egg!

As for getting a resounding NO from optoms about whether lenses damage the eye - that is because there are no definitive studies on the subject and the reason for that is not lack of willingness, rather the ethics of asking people to leave out lenses altogether in a randomised trial is simply not acceptable.

As Gareth said, if you have been fitted with a contact lens privately that works well and is not causing any problems, some hospitals are agreeing to continue supply if the practitioner will supply a prescription. Some hospitals insist they then take over total care - others are more flexible.

Another way round is to research where you can get the lenses you wish to try under the NHS system and ask your GP to be transferred there.

Where there is a will there is a way, quite often.

Lynn

[Fordy]

Lynn,

To be honest I am fed up with the whole thing.
6 months on from initial lens fitting I find myself with one lens that is good ,one that is poor(hybrids) and vision that has detioriated to an extent tnat I am struggling on with specs that give poor vision.
They will not consider soft lenses and i really wish I had not gone down tnis route.

I have a hospital appoitment next month so we will see where tnat takes me.

Thanks for the information.